This invention relates to apparatus for generating and directing ultrasound energy and, more particularly, to an apparatus which is addressable to direct an ultrasonic beam to a specified region of a body, such as for selectively heating the specified region of the body.
The use of ultrasonic energy for diagonostic and for treatment purposes has come into widespread use. In diagnostic systems, ultrasound energy is directed into a body, and the characteristics of the ultrasound energy either transmitted through the body or reflected from the body are used to obtain information about the body's structure. In some systems, images of the internal body structure are formed, whereas other systems are non-imaging.
In treatment systems, ultrasonic energy is utilized to selectively heat an internal region of the body. A highly focused and powerful beam may be used to "burn out" undesired tissue, such as a tumor. Alternatively, a defined region of the body may be brought to a controlled elevated temperature for a relatively long period of time to obtain a desired effect, such as the demise, retardation of growth, or other change in nature of undesired cells in the region. These techniques are known generally as regional hyperthermia.
In applicatins where ultrasonic energy is used to obtain a controlled heating pattern in a defined region of a body, it is generally desirable to form a beam of ultrasound energy that can be accurately directed to the body region to be heated, and accurately movable over the region to obtain a desired heating pattern. There are various known prior art techniques for generating focused ultrasound beams that can be directed to a specific position in a body or can be scanned over a desired pattern in the body. Most such systems suffer one or more of the following disadvantages: lack of accuracy, lack of operator flexibility in directing the beam, unreliability, and undue complexity or expense.
It is among the objects of the present invention to provide a system which overcomes these disadvantages.